The present invention relates to manufacturing semiconductor devices or the like and, more particularly, to a process management system for a semiconductor manufacturing line with the aim of developing products in a short time and improving the yield.
A process management system of a semiconductor manufacturing apparatus is generally constructed in a client-server system. To an analysis station as the client and to a data base and an image file as the server, a wafer surface extraneous substance inspection apparatus and a pattern defect inspection apparatus for detecting defects produced on the semiconductor manufacturing line such as extraneous substance particles attaching on a wafer surface and pattern defects, an optical review apparatus for checking the detected defects, an SEM (scanning electron microscope) review apparatus and an FIB (focus ion beam) apparatus, and a probe inspection apparatus and a testing apparatus for testing operation (function, performance) of an LSI (large scale integration circuit) are connected through a communication circuit.
Inspection information obtained by the inspection apparatus and the testing apparatus is collected online into the data base, and image information on the process defects and LSI operating defect points obtained by the review apparatuses and the FIB apparatus is collected on-line into the image file.
The information collected on-line in such a manner is used for pointing out important defects, for diagnosing the defects and for taking a countermeasure against the defects.
In a system disclosed in Japanese Patent Application Laid-Open No. 3-44054, each of the probe inspection apparatus, the extraneous substance inspection apparatus, the visual inspection apparatus and the like has a data analysis station as a means for efficiently taking such a countermeasure. The analysis station is provided with arrangement information of chips on a semiconductor wafer defined on the kind-by-kind basis so as to have a function to judge which chip a defect or the like belongs to. Thereby, a situation of occurrence of defects and the like can be known on the chip-by-chip basis. Further, by connecting between the above-mentioned inspection apparatuses through a communication line, the situation of occurrence of defects and the inspection results of the defects can be understood.
Furthermore, the display mode of the output results is unified so that the output results are easy to understand when the data is analyzed.
Further, Japanese Patent Application Laid-Open No. 48-39172 discloses a construction in which defects are classified on the type-by-type basis, and a predicted yield on the process-by-process basis is calculated from a probability of producing a defective semiconductor caused by each of the defect types and number of the defects.
The above-mentioned conventional technologies are insufficient to analyze the defects, and also insufficient to point out the defects and diagnose occurrence of the defects since the number of items clarified as the result of the analysis is not so many.
In addition to this, there is a problem in that reliability of the predicted value of yield is low since the prediction of the yield is very rough.
An object of the present invention is to provide a process management system which is capable of effectively pointing out the defects and diagnosing occurrence of the defects and capable of predicting a highly reliable value of the yield.
1. The process management system in accordance with the present application has display modes as described below in order to perform data analysis.
(1) Distinguishing display based on data on wafers or chips:
According to the present invention, the distinguishing display for data analysis is performed based on various kinds of data on wafers or chips. Although the details are to be described in the section of Description of the Preferred Embodiments, the process management system of the present invention comprises the following display modes in order to more effectively point out the defects and diagnose occurrence of the defects.
Enlarged display based on defect inspection data
Display distinguishing between defects which have been reviewed and the other defects based on defect inspection data
Display distinguishing between scribe lines and the other regions or between defects on the scribe lines and defects on the other regions based on data on the kind-by-kind basis of wafer
Display distinguishing among regions having different characteristics obtained based on arrangement data of chips on a wafer
Display distinguishing among regions having different distribution states of defects which are obtained from a defect inspection apparatus or the like
Display distinguishing regions where a defect of the same kind is expected to repetitively occur on the region-by-region basis
Display of a defect density map and a defect probability map
Display recommending review positions for review work by combination of the various kinds of displays described above
(2) Display on the inspection apparatus-by-apparatus basis and on a manufacturing process-by-process basis:
Display dividing between processes
Display tracing processes
Display of defects changing with process
Further, the following is provided in order to make the above displays clear.
(3) Function for setting definition of defect size.
2. Prediction of the yield of wafers or chips on the wafer:
The process management system of the present invention has the following elements in order to make highly reliable yield prediction possible.
According to the present invention, the process management system is connected to inspection apparatuses for inspecting at least defects on a wafer through a network to form a data base and an image file by collecting inspection information and image information obtained in these inspection apparatuses, and the management system comprises a means for classifying the defects on the basis of combination of elements characterizing the defects of a wafer, and a yield of the wafer or a yield of the chips on the wafer to the combination of elements is obtained based on a predetermined correlation table of yields of wafers or chips on the wafers to combinations of defective elements.
By the construction described above, the yield can be more strictly predicted based on the characteristics of defects since the defects can be classified in detail on the basis of the characteristic of defects.
Therein, it is preferable that the combinations of defective elements (defect classification) used in the correlation table are precisely set in a strong correlation with various kinds of faults as a premise. Further, the process management system of the present invention comprises a means for obtaining the strong correlation.
3. Data management:
In the present invention, the inspection data obtained from the various inspection apparatuses is managed by the following management means. The details are to be described in the section of Description of the Preferred Embodiments.
(1) Encipherment of inspection information
(2) Setting of management reference values
(3) Automatic reporting function
(4) Common download function